KOSHER – Jewish dietary laws
The Jewish dietary laws specify what foods are permissible and how food is to be prepared in order to be kosher. These laws are laid down in the Old Testament, the Talmud, and in later rabbinical writings. Jewish food is subject to these rules. The following notes relate to the dietary rules which enable even strictly Orthodox Jews to eat a particular dish.
Foods and the dishes produced from them which follow these rules are "kosher" (Hebrew for pure, suitable) and can therefore be eaten. The opposite is “treif,” which means “impure”, i.e. something which Jews are not allowed to eat.
The only mammals that are considered kosher are those which chew the cud and have a cloven hoof (e.g. cows). That means that pork, for example, is to considered “treif”, i.e. not kosher.
Among the other animals, birds of prey and fish without fins, gills and scales are forbidden. This ban applies for example to sturgeon, which has plates instead of scales. This means that genuine caviar is also forbidden, together with lobster, crayfish, mussels and squid. Other treif foods include all reptiles, frogs, worms, mussels, snails, spiders, insects and the like.
On the whole, vegetarian foods are considered kosher. An important exception is wine which has been prepared by non-Jews. To be on the safe side, ready-to-eat meals prepared by non-Jews are also considered not kosher. These prohibitions can be countered by regular checks of the production facilities by a rabbi and having a Jew light the flame for cooking (on the whole, a small pilot light which is on all the time is used for this purpose).
During the eight days of Passover there are additional rules to avoid eating any kind of yeast or leaven..
The Jewish dietary laws also specify how a warm-blooded animal – i.e. a fowl or mammal – is to be slaughtered. This is done by kosher butchering (shechita), in which a very sharp knife is used to sever the animal’s carotid artery and windpipe, after which the animal is suspend with its head down in order to drain all the blood. This process can only be carried out by a qualified shochet (ritual slaughterer). The length of the knife is determined according to the animal to be slaughtered. An Orthodox Jew is strictly forbidden to consume any blood, and Jewish food preparation has a series of techniques to remove the last drops of blood from a piece of meat.
Not all parts of a kosher animal which has been slaughtered in compliance with the rules of Orthodox Jewish food preparation may be eaten. A particular sinew must not be eaten, and in the case of mammals the fat deposits round the stomach, rumen, kidneys and other entrails are forbidden. Top-quality kosher meat is called “glatt kosher”.
Milk and meat
In the five books of Moses of the Old Testament, the same sentence is repeated three times. It is generally translated as follows from the Hebrew: “Thou shalt not seethe the kid in its mother’s milk.” The Talmudic writings in particular have interpreted this sentence as prohibiting the preparation of the meat of warm-blooded animals (i.e. mammals and poultry) together with dairy products (butter, yoghurt, cheese or similar). After a dish made of dairy products it is permitted to immediately eat a meat dish, but after a meat meal it is necessary to wait for six full hours before being allowed to eat something “milky” again.
Orthodox Jews interpret this separation of milk and meat products so strictly that they use separate utensils and dishes for preparing and eating milk and meat products. Some of them also use separate refrigerators and stoves.
Plant-based foods are considered neutral and can be used with both “milky” (milchig) and “meaty” (fleishig) dishes. Fish is also considered neutral or parve.